Method of and apparatus for treating parts



Dec. 10, 1968 w. E. ENGELHARD &

METHOD OF AND APPARATUS FOR TREATING PARTS 2 Sheets-Sheet l Filed Feb. 2, 1966 wr m f F'IG. 3

/NVENTOR w. E. ENGELHARD BY ATTORNEV Dec. 10, 1968 w. E. ENGELHARD 3415694 METHOD OF AND APPARATUS FOR TREATING PARTS 2 Sheets-Sheet 2 Filed Feb. 2, 1966 f/ I r/////// l /////////////////////////l///////////////////// IS /NVENTOR flu/ Z ENGEL HARD TTORNEV United States Patent O 3,415,694 METHOD OF AND APPARATUS FOR TREATING PARTS William E. Engelhard, Apalachin, N.Y., assignor to Owego Heat Treat, Inc., Owego, N.Y., a Corporation of New York Filed Feb. 2, 1966, Ser. No. 524,590 6 Claims. (Cl. 148-13) ABSTRACT OF THE DISCLOSURE This disclosure describes a method and apparatus for treating metal parts. The parts are mounted on a platform and enclosed by a heat shield after being heated to an initial temperature. The parts, the platform and the shield are lowered into an oil bath. As they are lowered, heat from the parts causes the oil to bubble and emit gases that are entrapped by the heat shield. The entrapped gases hold the heat shield at the oil line as the platform and parts are lowered into the oil bath. A pipe containing a valve is connected to the heat shield; the pipe has a downwardly projectng end. When the valve is opened, the gases in the heat shield escape and are projecte d onto the surface of the oil bath. As the gases escape, the shield lowers to again cover the parts. Thereafter, the parts, the platform and the shield are removed from the oil bath. Oil contained in the shield around the parts escapes through apertures in the bottom of the shield.

This invention relates to the treatment of metal parts which have been previously heated to critical temperatures, to progressively and `conformly cool them. The previously heated articles are positioned in a quenching medium, usually in an oil selected by boiling point or boiling range to fit the M -M range of the steel parts being quenched. An inverted U-shaped hood or heat shield is positioned in the tank and descends onto the articles and holder. Due to the intense difference in temperature between the quenching medium and articles or workpieces, gases are generated which enter the heat shield and hold the latter substantially above the articles, thus exposing the latter to full heat transfer interaction with the Volume of quenching medium in the tank.

It is preferable that the articles be surrounded by a more limited Volume of quenching medium so that the latter and the articles will progressively effectuate a heat transfer action slowly to attain gradual and uniform cooling. Such action is, however, partially negated where the heat shield, in practice, descends only upon the termination of generation of the gases flowing upwardly from the articles.

Pursuant to this invention, the moment of descent of the heat shield is accurately controlled and may be hastened to a time when the heat shield would otherwise be held up by gases, to thus protect the workpieces from continued exposure to the entire Volume of quenching Inedium.

Another feature of this invention is to provide automatic means for safely deflecting and releasing the entrapped gases, enabling the shield to descend onto and over the workpieces, to achieve the action above referred to.

A further feature of the invention is the provision of means for safe release of the gases, flame and dangerous vapor generated and accumulated in the heat shield during the direct boiling phase, directing the same onto the generating medium rather than the atmosphere and thus eliminating risk of fiame throwing and hot oil splattering.

Another purpose of this invention is to provide a safe procedure for removing work at high temperature from 3,415,694 Patented Dec. 10, 1968 ice the quench for straightening, forming or other Operations before it has passed through the M -M; range.

Pursuant to the invention, the heat shield may be lowered onto the workpieces while the latter are still so hot as to boil the quenching medium and generate gases.

The drawings, illustrating procednes and devices useful in carrying out the invention, and the description below, are exemplary only of the invention, which shall be deemed to cover all other devices and procedures coming within the scope and purview of the appended claims.

In the drawings, wherein similar :reference characters indicate like parts:

FIG. 1 is a vertical, elevational, partly sectional and partly fragmentary view of an apparatns for heat treating parts, pursuant to the invention, with the heat shield held elevated at the quenching medium level by the entrapped vapors escaping from the heated work,

FIG. 2 is a similar view, showing the heat shield descended over the workpiece, for progressive, uniform, cooling effect, on the release of the gases previously entrapped in said heat shield, and pursuant to the invention,

FIG. 3 is a fragmentary, elevational view of the parts of the device, including a mechanism for actuating the discharge valve in the upper portion of the heat shield, to release the gases automatically.

As shown in the drawings (FIG. 1) the parts or workpieces 10 generate gases 11 due to the workpieces having been previously heated to critical temperature as above noted, substantially above the temperature of the oil or other quenching medium 12, in the tank 13. Heat sheild 14 is lowered into the tank and onto the platform or holder 15; pipe 16, which may be solid at its lower portion 17, is secured as at 18 to the work holder, or platform 15, the upper portion of the pipe 16 being preferably hollow (FIG. 2). An aperture` 38 is provided in the pipe at or preferably just below the top 19 of the heat shield; gases may be admitted to the pipe 16 through a -coupling 29 at the upper end thereof, from pipes 20, 21, connected respectively to sources of gas supply. The parts 10 may be bathed in one or more gases introduced through the pipes 20, 21 and 16 during heating and transportation of the parts from' the furnace into the tank, and if dcsired, similarly on removal of the parts from the quenching tank. The heat shield 14 is closed at its upper end by a cap 22 which may have telescopic slidng engagement with the pipe 16 and may 'have a gasket 23, said cap being welded or otherwise secured to the extension 24 of the heat shield 14 as at 28.

A bracket 30 may be secured to or formed unitarily with the coupling 29 to facilitate el evatng or lowering `the assembly by suitable means such as a chain or hoist, schematically shown at 31, which may be used in con nection with an overhead beam or rail, etc. to transport the assembly from the furnace at which the workpieces 10 have been previously heated to their critical temperatures (as above noted), to the quenching tank 13.

On lowering the assembly into the quenching tank 13, the holder 15 and the work parts thereon descend to the bottom of the tank and the parts generate gases 11 due to their heat transfer nteraction with the quenching medium 12, which may be oil or the like, having a level line 32 preferably below the upper, open end 33 of the tank. The gases 11 become (FIG. 1) entrapped within the heat shield 14 and hold the latter essentially at the oil lever line 32, or in any case, substantially above the workpieces 10, exposing the latter to the full heat transfer contact with the entire quantity of quenching medium 12 of the tank 13. It is preferable that the parts cool progressively slowly; rapid cooling results in Shock and weakening of the parts and often in fracture thereof.

In accordance with the invention, the heat shield 14 is provided with a valve discharge port or pipe 34 extending from and opening into the extension 24 of the heat shield, above the upper end 19 of the latter; discharge pipe 34 has a downwardly directed opposite end 35, and a valve 36, intermediate the ends thereof, having a handle 37. The operator, on opening valve 36, may release the entrapped gases, flame and vapor and thus accelerate the moment of descent of the heat shield 14 onto the workpieces in enveloping relation (FIG. 2). The discharge end 35 of the pipe 34 is downwardly directed toward the quenching medium 12; thus the vapors, gases and flames within the heat shield may be safely direeted onto the oil 12, eliminating the risk of fiame throwing and hot oil spatter, likely to occur if discharge is in 'any direction other than onto the quench.

To remove work treated pursuant to the invention CO or other inert gas is introduced through pipe 16 and the assembly is (30, 31) elevated so that as the assembly is lifted oil Will seep out of the interstiees between the lower end of the heat shield and the platform the oil will thus be replaced by the CO and not by ambient air; when the shield is then lifted away from the platform the shield will be full of CO gas but free of vapors and the work may be removed with the use of `asbestos gloves.

As shown in FIG. 3, a solenoid 40 may be mounted as at 41 onto the pipe 34 and connected, as schematically shown at 42 with the valve handle 37 in an arrangement such that on actuation of the solenoid, the valve handle 37 will be rotated to open the valve and, upon the return stroke of the solenoid, to close the valve. The solenod may be connected to a suitable circuit by any convenient means which may be ncorporated in or formed apart from cable 43 for the switch 44 controlling the solenoid circuit. This arrangement is desirable where, for example, the operator is located at a point remote from the tank, or where it is otherwise deemed more convenient to `actuate the valve electrically rather than (FIG. 2) manually.

As above noted, pursuant to the invention, the quenching medium 12 is selected with 'a boiling point or boiling range (vapor or gas release) to correspond with the M -M range of the parts being quenched.

While the foregoing disclosure of exemplary embodments is made in accordance with the Patent Statutes, it is to be understood that the invention is not limited thereto or thereby, the inventive scope being defined in the appended claims.

I claim:

1. A method of treating metal parts that have been previously heated to a critical temperature comprising the steps of:

mounting the parts on a platform under a heat shield;

suspending the parts, the platform and the shield over an oil bath;

lowering the parts, the platform and the shield into the oil bath;

entrapping escaping gases in the heat shield so that the heat shield is held near the surface of the oil bath as the parts and the platform :are lowered into the bath;

controlling the rate of removal of the gases from the heat shield by utilizing a pipe, including valve means, connected to said heat shield;

removing gases from the heat shield so that the heat shield is lowered over the platform and the parts, said gases being projected onto the surface of the oil bath as they are removed from the heat shield; and

raising the heat shield, the platform :and the parts from the oil bath.

2. A method of -treating metal parts that have been previously heated to a critical temperature as claimed in claim 1 including the additional step of electrically controlling the value means.

3. Apparatus for treating metal parts that have been previously heated to a critical temperature comprising:

a metal treating bath that emits a gas when heated;

a platform for holding said parts;

a heat shield mounted over said platform and vertically movable with respect to said platform, said heat shield adapted to entrap the gases emitted by said metal t'eating bath when said heat shield, said platform and said parts are lowered into said metal treating bath;

lowering means for lowering said platform, said heat shield and said parts into said metal treating bath; and

controllable means attached to said heat shield for allowing the gases entrapped by said heat shield to escape, said controllable means being a pipe, including a valve, connected to said heat shield and having a nozzle that projects -downwardly so that said escaping gases are projected onto the surface of said metal treating bath when said valve is opened.

4. Apparatus for treating metal parts that have been previously heated to a critical temperature as claimed in claim 3 wherein said valve is electri2ally actuated.

5. Apparatus for trezting metal parts that have been previously heated to a critical temperature as claimed as claim 3 wherein said lowering means comprises a tubular rod structure projecting upwardly from said platform, and wherein said heat shield is mounted on said rod for vertical slidable movement.

6. Appara-tus for treating metal parts that have been previously heated to a critical temperature as claimed in claim 5 wherein said valve is electrically actuated.

References Cited UNITED STATES PATENTS 2,l42,l39 l/l939 Machlet 266-6 2,862,843 12/1958 Engelhard 148-157X 2,872,364 2/1959 Sherwood et al 148-153 OTHER REFERENCES Per'ys Chemical Engineers' Handbook, 4th ed., MeGraw-Hill Inc., 1963, pp. 6-35 thru 6-39 and 22-85 reied on.

CHARLES N. LOVELL, Primary Examiner.

U.S, Cl. X.R. 

